STAINED GLASS WINDOWS. By far the most important use of stained glass is its application to the artistic decoration of windows, usually termed glass painting, though properly speaking it is not painting at all. Originally, there was but one method of making ornamental glass win dows, and that was to produce the pattern in out line with finely made leaden frames, into the grooves of which pieces of colored or stained glass were fitted. It appears to have been a branch of art unknown to antiquity and to have been used in a primitive fashion in churches of the fourth and following centuries, the different colors forming not figures, but ornamental pat terns. These are described by early authors such as Prudentius, Sidonius, Apollinaris, and Gregory of Tours, but nothing of this period has been pre serted. The majority of windows up to the eleventh century were closed by thin slabs of alabaster or other translucent material often pierced by holes arranged to form patterns, as at Santi Vincenzo ed Anastasio and other Roman ehmkehes.
One of the best known of the early examples of the use of figures in glass windows is of the eleventh century in the former monastery of Tegernsee (Bavaria) ; like all of the first at tempts, they were only tasteful arrangements of colored glass in imitation of the stone mosaics used for floors, etc. Shortly afterwards in the twelfth century the monk Theophilus describes in his treatise the method of making such windows as the earliest ones at Chartres, Saint Denis, and Vendome. The centre of the steady progress throughout the twelfth and thirteenth centuries was in .Northern France. where the use of Gothic architecture, with its immense increase in the size of the windows, suddenly brought stained glass windows into prominence, not only as one of the most important accessories of architecture. hut as the one prominent color factor in the great Gothic interiors. As the windows occupied the entire wall-space between the piers, both in the aisle-walls and clerestories of the churches, they afforded the same opportunity for composi tion that the solid walls had previously offered to freseo-painting. The French cathedrals of the
thirteenth century at Le Mans, Chartres, Bourges, and to a less degree Rheims and Rouen, pre serve whole series of contemporary windows, which gave the type to other countries and to the succeeding century. Those of the Sainte Cha pelle in Paris are also of extreme beauty. The characteristics of the earliest Gothic windows are: multiplication of small figures in many sep arate compositions grouped in tiers or rows of framed medallions; rich and dark coloring; wide decorative borders; heavy leads bent so as to outline the figures or cut them in the deep shad ows.
The development during the fourteenth century was toward lighter coloring, larger figures, nar row borders, more ornamentation in the body of the windows, more delicate gradations of color, and increase of modeling, loss of simplicity, and tendency to mannerisms, while in the fifteenth century much clear glass was introduced into the backgrounds, and inscribed ribbons and archi tectural accessories became conspicuous, whereas the earlier windows are composed of many small and distinct pictures set in a groundwork of grisaille or of color ornament, the later ones comprising a single figure or picture for each light or even a composition occupying the whole window. The designers of the Gothic age did not, to any great extent, give the details of their pictures on glass as their suecessors—Renais sanee and modern—mistakenly attempted to do. but obtained their superb effects by a clear knowl edge of the interaction of colors. by juxtaposition of complementary colors, and the effect of dis tances; the technique being that of glass colored not on the surface, hut in the mass either by stain or incorporation. This branch of art was. therefore, governed by totally different artistic principles from those governing opaque painting (fresco, oil, tempera, tapestry, etc.) , and these principles were thoroughly understood.